Fluid operated chuck



Nov. 5 1935. J. Q. HOLMES ET'AL FLUID OPERATED CHUCK Original Filed Sept. 29, 1932 2 Sheets-Sheet 1 a as 72 1 1 -5 4/ a @fil/NVENTORS f w ATTORNEY Nov. 5, 1935. I J. Q. HOLMES ET AL ,0

FLUID OPERATED CHUCK Original Filed Sept. 29, 19:52 2 Sheets-Sheet 2 INVENTORS wfi - ATTORNEYd.

Xa4 QMISI VQZLZ KM Patented Nov; 5, i935 Miami in. or ans!) canon John Q. Holmes AndeR-son, Ind., and Leo C. Skippy, .Lockport, N. Y., asslgnors to General Motors Corporation, Detroit, Mich., a corporation of Delaware 9 Claims.

The invention relates to chucks and more particularly to fluid pressure operated chucks.

It is among the objects of the present invention to provide fluid pressure means for operating a chuck in such manner that more power is exerted by said fluid pressure means to release the work than is exerted by the same to clamp the work, thus assuring abundant power to overcome the considerable static friction between the gripping elements of the chuck andthe clamped work when releasing the latter.

Another object of the present invention is to protect the movable parts of the chuck from the oxidizing effect of cooling water which is flushing the clamped work while being operated upon.

This application is a division of our co-pending application Serial No. 635,316, filed Septeminvention will be apparent from the following description,'reference being bad to the accompanying drawings wherein a preferred embodiment of the present'invention is clearly shown.

In the drawings:

Fig. 1 is a plan view of a chuck embodying the present invention, certain parts thereof being shown in section.

Fig. 2 is an elevation of the chuck looking in the direction of arrow 2 in Fig. 1, that part of Fig. 2 which is shown in section being taken on the line 2-2 of Fig. 1.

Fig. 3 is a section through the chuck taken on the line 33 of Fig. 1.

Fig. 4 is a fragmentary section taken on line 4-6 of Fig. 1.

Referring to the drawings, the chuck is generally designated by the reference numeral l0 and comprises a frame I 2, having a cylindrical the ' bore M which receives jaw carrying frames I 6 and I8; having cylindrical peripheries in which gear segments 20 and 22, respectively, are cut. The gear segments 20 and'22 mesh with racks 2t and 26, respectively, of rods 32 and 3%, respectively.

These pistons 28 and 30 are slidable in cylinders 36 and 88,- respectively, which are provided by an integral cylinder block 40, clamped between end plates 42 and 44 which are bolted to the chuck frame l2 in any suitable manner. Frame It is confined between frame l8 and a splash pan 4t, and frame 18 is confined between frame it and a bottom plate 68, secured by-screws $8 to frame l2. Each of the frames i6, i8 is provided with radial notches 52 each of which guides for radial movement a jaw 54; having teeth 55 for gripping a cylindrical workpiece A. A part roller-shaped portion 56 of each jaw 54 is received by a socket portion 58 01' a glide shoe 60 which is adapted to engage with one of a plurality of camming surfaces 62, provided by cam rings 64 which are secured in any suitable manner to frame l2. The 5 I laws 54 are normally urged into registry with the glide shoes 60 and the latter into engagement with the camming surfaces 62 by leaf springs 65 (see Fig. 3), attached with one end to the heads 66 of screws 68 which are threaded into the 10 frames l5 and H3. The free ends of these leaf springs are received in V-shaped notches 10, pro-- vided by the jaws .54. Assisting the rather stiif leaf springs 65 in their function are a plurality of compression springs 12 which are seated in an- 15 nular recesses 14 of the jaw carrying frames and urge the leaf springs 65 and therewith the'jaws 54 in such direction that the glide shoes 60 are norinallymaintained in engagement with their respective camming surfaces 52. When the pis- 20 tons 28, 30 move toward the right as viewed in Figs. 1 and 2, the frames 16 and '18 will rotate in the direction of arrow 16 in Fig. 1, thereby causing the glide shoes 60 to ride progressively toward those portions of the camming surfaces 62 5 which approach the center of the chuck. Such movement of the glide shoes 68 and associated Jaws 56 results in a gripping of the workpiece A by the jaws 56. When the pistons 28, 30 move toward the left as viewed in Figs.- 1 and 2, the 30 frames l6, 18 will rotate in the direction of arrow I8 in Fig. 1, thereby causing the glide shoes 66 to ride progressively toward portions of the camming surfaces 62 which lead away from the cen-' ter of the chuck whereupon the jaws 54 will re- 35 cede from the workpiece A and permit the latter to descend by gravity to any desired destination.

Since the frictional resistance, encountered between the glide shoes 60 and the cammingsu-rfaces 52 is a slidingfriction, the coefdcient of. which is less than the coefficient of the static friction to be overcome before the frames iii. 18 can be rotated in a direction to effect release of a clamped workpiece, another cylinder block is provided which comprises two cylinders 82 45 and 86 in axial alignment with cylinders 38 and 38, respectively. These cylinders 82 and-86 receive pistons 86 and 88 which are adapted to aid the pistons 2@, so respectively, in their movement toward the left as viewed in Fig. 2 in order jointly 50 to overcome the already mentioned considerable static friction between the glide shoes and their respective camming surfaces when undertaking to release a clamped workpiece. Cylinder block 86 is clamped between end-plate s4 and another 55 block 48 in any suitable manner. aligned pistons 28, 88 and 88, 88 are connectible for unitary movement by rods 82, passing through suitable stufllng boxes 84 which are threaded into the intermediate end wall 44. When fluid pressure, such as oil, is admitted to the cylinders I 88 and 38 to move the pistons therein toward the left as viewed in Fig. 2, the same fluid pressure is also permitted to enter cylinders 82 and. through a duct 88 and a groove 88 whereby the 7 piston; 88, 88 are also moved toward the left as viewed in Fig. 2 and by intermediation oi the rods 82 assist the pistons 28, 88 in theirmovement in the same direction which results in the release of a clamped workpiece A. Fluid pressure is permitted simultaneously to enter the right-hand sides of the cylinders 38, 88 and 82, 84 as viewed in Fig. 2 through a pipe I88 which, as shown in Fig. 2, communicates with the right-hand sides of cylinders 82, 84 through-the earlier mentioned duct 88 and groove 88 and with the right-hand sides of the cylinders 88, 88 through a duct I82 and a groove I84 in the intermediate end wall-44. Fluid pressure is admitted to the left-hand side of cylinders 88, 88 only through a pipe I88 which communicates with a duct I88 and a groove III,

provided by end plate 42. The pipes I88 and I88 may be conected to any conventional type valve (not shown) which is in communication with any suitable source of fluid pressure and which, while permitting fluid pressure to flow into pipe I88 and to the left-hand side of cylinders 88, 88,also permitsventing of the right-hand sides of cylinders 38, 38 and 82, 84 through pipe I88, and vice versa. The operation of the conventional valve which may be manual or automatic and which controls the admission of fluid pressure to the cylinders does not form part of this invention, the explanations given'with respect to the valve being sufllcient for the full understanding of the function of the auxiliary pistons 88, 88.

Referring particularly to Fig. 3, there is shown an oiler I28 which is adapted to lubricate the relatively sliding surfaces of the jaws 84, the frames I8, I8 and the camming surfaces 82, in order to prevent rusting. of these surfaces under the influence ofcooling water from the splash pan 48 into which water is continuously poured in order to flow from there past the workpiece A while being operated upon by a tool such as bits boring the interior of the workpiece. Extending into the oiler housing I22 are two tubes I 24 and I28 each of which is closed on top and has an opening I28 in its cylindrical wall. These tubes I24, I28 extend through the housing I22 and are threaded into ducts I38 and I82 respectively, of

' bracket I2. The ducts I88 and I82 are in communication with annular chambers I84 and I 88. Chamber I84 is formed by the camming surfaces 82 of one of the cam rings 84, the external surface of frame IS, the bottom surface'i88 of splash pan 48 and the top surface I48 of bracket I2, while chamber I38 is formed by the camming surfaces 82 of the other cam ring 84, the external surface end plate so, the latter being bolted to cylinder The axially I88, air is permitted to enter the oiler through a conventional check valve I44. During radial movement of the jaws 84 away from the center of the chuck, the oil in the chambers 'I34 and I38 and also in the oiler I28 is slightly-compressed due to the fact that the .air on top of the oil supply within oiler I28 cannot escape through check valve I44 and is slightly compressed. Some of the oil under pressure in the chambers I34, I88

will therefore, escape between the relatively slid- 1 ing surfaces of the Jaws 54 and the corresponding tion between the glide shoes 88 and their respective camming surfaces 82 while work is clamped bythe jaws. 25

, While the embodiment of the-present invention as herein disclosed, constitutes a preferred form,

it is to be understood that other. forms might be adopted, all coming within the scope of the claims which follow. 30 We claim: I l. A chuck including clamping means, and

power means for operating the'clamping means,

said power means including a plurality of fluid" pressure operated pistons, all of them being operated to release clamped work and only part of them being operated to clamp work.

- 2. A chuck including clamping means, means including a plurality of pistons for operating the clamping means, two main fluid pressure con- '0 duits, a plurality of cylinders receiving the pistons, said cylinders having ducts which provide communication between the cylinders and the conduitsin such manner that admission of fluid pressure to one of said conduits causes all pistons to be operated, and admission of fluid pressure to the other conduit causes a fewer number of pistons to be operated.

3. A chuck including clamping means, and fluid pressure operated means for actuating the clamping means, said fluid pressure operated means including a double acting and a single acting piston, and means for admitting fluid pressure to the single acting piston to cause the latter to assist the other piston in releasing clamped work.

4, A chuck including clamping means, fluid pressure operated means for actuating the clamping means, said fluid pressure operated means including a double acting and a single acting piston, and means for simultaneously admitting fluid so pressure to both pistons whereupon the single acting piston assists the other piston in releasing clamped work, and for admitting fluid pressure to the double acting piston only to clamp work.

5. A chuck comprising, in combination, a body providing a cavity accessible through a plurality of slots in said body; a plurality of clamping jaws received and guided for movement to and from the work by said slots; and a lubricator above the level of the cavity and communicating with the latter-so that said cavity is filled with lubricant, said lubricator including means for causing a restricted flow of lubricant only from the cavity to the lubricator when the Jaws move in a direction whereby the cavity is reduced so that some lubricant leaks from the cavity through the relatively sliding surfaces oi the jaws and guide slots and forms a him of lubricant between these surfaces.

6. A chuck comprising, in combination, a body providing a cavity accessible through a plurality of slots in said body; a plurality of clamping jaws received and guided for movement to and from the Work by said slots; a lubricator above the level of the cavity and communicating with the latter so that said cavity is filled with lubricant; and a check valve on the lubricator permitting air to enter the latter when the cavity is enlarged during movement of the Jews in a certain direction, and preventing th' discharge of air from said lubricator when the lvity is reduced during movement of the jaws in another direction so that the trapped air within the lubrieator is compressed and. causes lubricant to leak from the cavity through the relatively sliding surfaces of the jaws and guide slots forming a film of luhri cent between said surfaces.

7. A chuck including clamping means; and

plurality of power operated means for actuat his the clamping means, all of these actuating means being operative to release clamped work and only part of them being operative to clamp work.

8. A chuck including clamping means; and means for operating the clamping means, said operating means including a plurality oi cylinders and pistons in tandem order and two fluid pressure conducting conduits, one of said con- 5 duits communicating with'one end of one cylinder,

and the other conduit communicating with the opposite end of said cylinder and with the corresponding end of the other cylinder.

9. A chuck including clamping means; and 10 means for operating the clamping means, said operating means including a plurality of cylinders and pistons in tandem order and so arranged that a partition separates two successive cylinders and defines end walls for both cylinders, 15

and two fluid'pressure conducting conduits, one of said conduits communicating with one end of one cylinder, and the other conduit communicating with the opposite end of said cylinder and with the corresponding end of the other cylinder 20 through ducts provided in the cylinders and merging into a single duct in the partition, said single duct being in direct communication with said other conduit.

JOHN Q. H0. '25

LEO G. SI-MPY. 

